IN-VITRO POSTANTIBIOTIC EFFECT FOLLOWING REPEATED EXPOSURE TO IMIPENEM, TEMAFLOXACIN, AND TOBRAMYCIN

The postantibiotic effect (PAE) following three consecutive 2-h exposu res to imipenem, temafloxacin, and tobramycin was determined in Pseudo monas aeruginosa. A PAE and a bactericidal effect were consistently ob served for imipenem following each cycle of drug exposure and regrowth . In contrast, the PAE increased with repeated exposure with temafloxa cin (1.8 to >5 h), but disappeared with tobramycin by the third exposu re (0.9 to 0 h). These data show that the in vitro PAE may change with in a strain following multiple cycles of drug exposure and bacterial r egrowth.